1. Field of the Invention
The present invention relates to constructions and formulations for candles, particularly candles in which the body of the candle is substantially transparent or translucent.
2. The Prior Art
Candles that are used for informal occasions (i.e., candles that are not used for religious ceremonies or similar formal occasions) are often provided in other than the simple waxy xe2x80x9coff whitexe2x80x9d color. Such candles may often be brightly colored and decorated with the various xe2x80x9cadd onxe2x80x9d forms (e.g., wax forms like grape clusters, etc.). Another format, in which candles may be made in a decorative manner beyond their mere utilitarian function, is to make the candle clear.
It is well known that candles can be made in numerous designs and may come in many forms. Although every candle may vary widely in utility, scent, color, texture and even clarity, they most widely fall into two general categories. These categories are listed and defined below (definitions courtesy of NCA, National Candle Associationxe2x80x94www.nca.org).
1. Filled Candlesxe2x80x94Those candles produced (filled) and used within the same vessel; and
2. Free Standing Candlesxe2x80x94Those candles which are rigid and generally free standing which are to be used on a heat resistant, non-flammable surface or on a candle accessory such as a votive holder or candle stick.
When making either kind of the two general candle types above; manufacturers must consider the formulation characteristics of the fuels to be used. Because a certain candle fuel composition will have certain chemical and physical properties associated with it, the fuel may or may not be well suited for one or both of the above-stated categories.
For example, traditional fuels that are too soft, perhaps whether by having a low melt point or low hardness value, cannot be used in a free standing application because typically they lack sufficient rigidity at certain temperatures or there is the presence of obvious oiliness about the fuel. These too xe2x80x9csoftxe2x80x9d fuel characteristics are common for very highly fragranced waxes, waxes containing oil and the newer gelled oils. Although it is possible to add ingredients or xe2x80x9cadditivesxe2x80x9d to these fuels to help reduce softness or oiliness, this typically increases cost. Therefore softer or oilier fuels, often being cost effective, are most well suited for the xe2x80x9cfilled candlexe2x80x9d, i.e., container applications.
Recent developments in gelled oil technology have resulted in candle fuels that are transparent. One form of candle fuel is exemplified by light oil, solidified by rubber-type compounds. One such candle fuel is manufactured and sold by Penreco under the name xe2x80x9cVersagelxe2x80x9d (formerly known as xe2x80x9cGeahlenexe2x80x9d). For the purposes of this application, this form of fuel shall be termed xe2x80x9crubberized gelxe2x80x9d fuel. Another form of candle fuel is exemplified by an ester-terminated polyamide, blended with a solvent to form a gel. Such a fuel is exemplified in U.S. Pat. Nos. 3,615,289; 3,645,705; 3,819,342; 4,332,548; 4,449,987 and may be referred to generally as xe2x80x9cpolyamide gelxe2x80x9d fuel.
While these fuels have achieved the desirable transparent/translucent characteristic, they have already exhibited limitations in their application to free standing candle types. These limitations are again associated with their inherent physical and/or chemical properties that include lack of rigidity, oiliness, tackiness, or brittleness. These transparent gelled oil candle materials are recognized as being best presented within solid, heat resistant glass or plastic final-use-containers. These same gelled oil candle fuels use polymer type gellants, commonly with caulk, adhesive or rubber formulations which are often very sticky when molten or mixed with oils, rendering themselves as materials not suited for removal from candle molds that are often used to make free standing candles, both due to the removal difficulties, and due to the further propensity of the candles to be easily marred, once the candle has been removed from the mold.
The candle gel known as Versagel (Geahlene) from Penreco is an amorphous blend of block polymer and fuel (hydrocarbon oil) that exhibits a resultant thickened viscosity rendering a nearly solid or semi solid and tacky rigid fuel form at room temperature. Ultimately as the gel is heated by a candle flame, it reaches a temperature range best described as its melting temperature, where dramatic loss in viscosity occurs, allowing the now molten fuel to be wicked up and xe2x80x9cfuelxe2x80x9d combustion. This viscosity and resultant rigidity of the fuel is also subject to diminish, less dramatically, with increasing exposure to even room temperature conditions over time. This behavior is termed xe2x80x9ccold flowxe2x80x9d and is exacerbated with the presence of fragrance materials in the formula. Manufacturers address this cold flow problem by using less fragrance additive or by placing a temporary clear plastic lid over the top opening of the candle container, often with an aperture for the wick, to protect the filled candle unit from cold flow should the candle be placed on its side during shipping. This also protects the gel from unsightly fingerprints by restricting consumers curious fingers access to the gel surface. In summary, this gelled oil is subject to having a non-fully self-supporting property and is best suited for insertion into some sort of filled container application. It should be noted that the presence of increasing polymer concentrations can slow the process of cold flow, but such increased polymer concentrations are known to hinder the wicking process of molten fuel, thus producing a smaller, dimmer flame.
Clear polyamide gelled oil fuels are available and also possess high oil concentrations. Being at least partially crystalline in structure, this technology is said to be able to attain rigid gelled oil sufficient for a free standing candle application. However, the literature also suggests that this technology has a history of being prone to fracture, marring, xe2x80x9cbleedxe2x80x9d or exhibit chemical phase separation in the pool of molten fuel surrounding the wick during burning.
The xe2x80x9cbleedxe2x80x9d characteristic is more technically known as syneresis, the phenomenon that oil is physically being squeezed out of the candle fuel material because of shrinkage and excessive chemical crosslinking of the polymer in the gelled fuel body. This results in a tactile sensation of being excessively oily with a tendency to accept fingerprints or mar, and subsequently the internal gel matrix becomes increasingly brittle. Polyamide gels in common with candle gel described above are notoriously sticky; containing polymers suited for adhesives and caulking formulations, and is difficult to remove from a candle mold. Because of these properties polyamide gel candle compositions are also widely recognized as being truly suitable for use in a filled candle or solid final use container applications such as glass. Polyamide gels contain comparatively high percentages of gellant to achieve functionality, rendering a cost limitation as well.
The understood behavior of xe2x80x9cburning a candlexe2x80x9d is easily visualized and most non-technically described as the process upon lighting the wick the candle fuel core becomes molten, fuels the wick and the candle as a whole is xe2x80x9cburned downxe2x80x9d with time, where the fuel core surface, wick and flame all remain spacially constant to each other, they burn down leaving a deeper vertical distance relative to top edge the original candle and container. This proceeds until the candle is exhausted or extinguished.
In so being most notably suited for use in solid containers such as glass or heat resistant plastic, the production of a freestanding transparent or translucent candle present several challenges. Manufactures can only approximate this desired design by using a clear glass or solid plastic tube that serves to provide the support or protection for the candle fuel. However, glass tubes being expensive, may crack or shatter in the presence of even slight temperature changes relative to the internal and external boundaries of the candle. Heat resistant solid plastic tubes require short, rigid and transparent qualities. During consumption, this distance down that the candle has burned may eventually hinder the availability of oxygen to get to the flame to support efficient combustion. This may result in the production of unsightly, undesirable and potentially hazardous emissions (known as coking) and flammable soot build up. Subsequent use may become progressively difficult and unsafe, as consumers must hold a match precariously downward to re-ignite the wick and are apt to release the match abruptly to avoid injury. This resultant collection of debris can itself be very unsafe.
An example of a prior art transparent candle having a substantially rigid supporting container is found in Linton et al., U.S. Pat. No. 4,332,548. The candle of the Linton et al. ""548 patent includes a transparent candle container made in a heatresistant plastic or glass material. The primary transparent candle composition is that such as is disclosed in Gunderman et al., U.S. Pat. No. 3,819,342. The Linton et al. ""548 candle also includes a second lower transparent safety layer which is fabricated from a substantially non-combustible composition so that once the candle has burned down to this lower safety layer, the substantially non-combustible composition material will melt and envelope the wick and any stray particulate material, such as the remains of the wick, remains of matches, etc., which could result in a flaring or sudden explosion of flame. The non-combustible material of the safety disk will thus entrap such extraneous particles as well as the wick remainder and extinguish the candle.
The trend in industry is moving to reduce, eliminate, or optimize the costly xe2x80x9ccontainerxe2x80x9d as a factor in product cost. One approach to achieve this goal is known as the xe2x80x9crefillxe2x80x9d concept. Here, a manufacturer sells a filled candle container with an attractive glass, and also sells individual replacement fuel cores (candles) of various scent and color designed for the original glass. This saves the consumer money, having only to discard the spent candle remains of the used candle and not the glass.
While the National Candle Association attributes the #1 safety hazard in the industry as being from injury sustained when consumers remove the xe2x80x9cspent candle remainsxe2x80x9d from containers. Consumers typically use sharp objects to pry the remains and xe2x80x9cjabxe2x80x9d themselves or the glass shatters and lacerates their hand.
It has long been an ultimate technological goal in the candle industry to provide an xe2x80x9cidealxe2x80x9d candle material that is clear, rigid, self-supporting, conducive to fueling and propagating a controlled flame using a wick, can be colored, fragranced, not subject to marring or fingerprinting, or excessive brittleness (shattering).
Many, but not all, of the foregoing goals have been approached or possibly met, through the gelled oils described herein.
To date, however, no such perfect xe2x80x9cclear waxxe2x80x9d equivalent has been attained, and in each of these xe2x80x9cclose approachesxe2x80x9d, where a deficiency in design, performance or economics has been noted, the problem has been addressed through less desirable solutions, such as the plastic cover disks, previously described.
In the pursuit of optimizing container costs, refill concepts abound. To provide consumers with xe2x80x9cclearxe2x80x9d free-standing candle products, solid coatings, rather than glass or plastic containers, have been proposed to address or overcome the deficiencies of the previously mentioned state-of-the-art gelled-oil fuels.
Several such coatings are described in International Publication WO 98/17243. The components referred to in that reference are preferably polymer resins such as fuel oil gelled with a polyamide or styrene acrylic resin. These candidate materials are described with respect to their ability to meet rigidity and clarity requirements, as well as the materials"" propensity to be sufficiently adhered to a fuel body for the purposes of support of the fuel and protection from marring. Pure polyamide type resins were evaluated against pure block-polymer resins to quantify and compare rigidity data. The same relative comparisons were made regarding clarity. Each of the methods used a protocol where molded objects of the respective materials (and others) were made and scrutinized for their performance.
In the attempt to evaluate materials viable for solid candle coatings, 2.5xc2x10.4 mm and 5.5xc2x10.4 mm thickness molds were made of various polymer resins.
Polyamide resin ETPA performed well in clarity, provided the various mars and smudges were diligently polished or removed. Rigidity was quantified as well for this material when a sheet of 3 mm thickness was evaluated horizontally under the effect of gravity. In fact, these and many polymers were evaluated to the extent of understanding their solubility and hardness (brittleness) properties in the search for useable coating candidates. Even styrene based acrylic resins noted for their use in floor enamel products showed interesting data. Provided the dipping, spraying, or other techniques used would allow for proper adhesion to the fuel core or to the inside of a mold, the results indicate that a significant thickness of material would be required to virtually replace a glass container as an approximate simulation, retaining the approximate fragility and mass properties of these containers.
To make the container issues moot; efforts have been made in the prior art to provide a clear/transparent/translucent candle construction. International Application Publication Number WO 98/17243 is directed, in part, to ester-terminated polyamide gel bodies, including transparent candles, in which the fuel core material is a polyamide gel. This reference additionally discloses the use of a solid coating for the fuel core that is a component, preferably a pure gellant polymer (polyamide resin or a styrene acrylic resin). These materials, containing functional or polyfunctional molecular components such as nitrogen or organic acid group based components would have melting points quite close to the melting points of the polyamide gel fuel core material, and would be readily soluble in the pool of molten fuel core material, thus contributing actively to the combustion of the flame, as if a clear solid wax glass replacement had been achieved. Currently no such clear solid wax glass replacement has been disclosed.
In addition, the coating was described as being applied either by spraying, dipping, or by coating the inside of a mold with the coating material, and then pouring the fuel core material into the mold. In any event, while the coating material, being a more pure polyamide resin or acrylic resin, might be somewhat harder and more rigid than the fuel core, such coatings were clearly not considered to be the functional equivalent of a self-supporting container for the fuel core. That is, the brittle crystalline coating may help support the gel fuel core, but the mechanism is more in the manner of the fuel core giving the coating xe2x80x9csomething to hang ontoxe2x80x9d, in that the coating relies on its stickiness to cling to the fuel core, and less in the manner of a freestanding xe2x80x9ccontainer-likexe2x80x9d support. In addition, the solid coating, having a thickness in the range of several millimeters, for example, could contribute a significant percentage of the overall weight of the candle unit, adding to the cost, size and other physical limitations, in addition to being potentially brittle or easily marred.
It would be desirable to provide a candle unit that is less susceptible to direct handling concerns (marring by fingerprints, etc.) and general breakage issues.
It would further be desirable to provide a candle unit that is both clear/transparent/translucent, and cleaner burning.
It would also be desirable to provide a more cost effective candle unit having such see-through characteristics.
It would also be desirable to provide a candle unit that has an outer surface that is substantially non-oily, substantially non-tacky.
It would also be desirable to provide a candle unit that can be used independently of external or separate discrete receptacles, that can be removed from a mold easily, that is relatively free from cold flow (at typical ambient room temperatures), and does not require the use of an inserted supporting disk, as previously described.
An additional consideration in the manufacture of candles is the known characteristic of xe2x80x9cconventionalxe2x80x9d opaque wax candles to produce larger flames and thus stronger light, than comparatively sized clear or translucent gel candles.
As such, it would also be desirable to provide a gel candle that is capable of producing an improved quality of light, for its size, so that its limited light emissions can be exploited to maximize its overall rumination to more closely approximate a comparatively sized conventional wax candle.
These and other desirable characteristics of the present invention will become apparent in view of the present specification, claims and drawings.
The present invention is directed, in part, to a candle unit, comprising a fuel core, fabricated from a flammable fuel material, the fuel material having a fuel core melting temperature range. A wick is embedded in the fuel core, for drawing up molten fuel material, for supporting a candle flame. A film surrounds at least a portion of the fuel core, the film being fabricated from at least one material, having a film softening temperature range, having an upper-end temperature that is greater than an upper-end temperature of the fuel core melting temperature range such that the fuel core material becomes liquid substantially sooner than the film becomes non-self-supporting due to softening, so that when the candle burns, a pool of molten fuel core fuel material forms on the top of the candle, around the candle flame, without immediately causing the film to become non-self-supporting, and a portion of the molten fuel core material is consumed, so that an upper surface of the pool is vertically spaced from a top edge of the film.
As the candle burns down, the top edge of the film is exposed to progressively higher temperature regions of the aura of the candle flame, and ultimately becomes non-self-supporting and recedes downward from the descending candle flame, while the pool of molten fuel core material is further consumed, so that a vertical spacing between the upper surface of the pool of molten fuel core material and the top edge of the film is maintained.
The film, according to one embodiment of the invention, may be fabricated from at least one material that, when molten, is not readily soluble in the molten fuel core material. The film may be fabricated from at least one layer of material selected from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes.
The film may have a single layer. Alternatively, the film may have at least two layers. The at least two layers may be fabricated from different materials. At least one of the at least two layers may be fabricated from at least one of the materials in the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes; and at least one of the at least two layers is fabricated from at least one of the materials in the group consisting of: polypropylene.
Preferably, the film has one of the following characteristics: transparent, translucent, opaque.
The film may include at least one active ingredient from the group consisting of: fragrance materials, air freshener materials, insect repellent materials, flame retardant materials, dyes, pigments, plasticizers.
The present invention is also directed, in part, to a candle unit, comprising a fuel core, fabricated from a flammable fuel core material, the fuel core material having a fuel core melting temperature range. A wick is embedded in the fuel core, for drawing up molten fuel core material, for supporting a candle flame. A film surrounds at least a portion of the fuel core, the film being fabricated from at least two layers, fabricated from different materials, the at least two layers being fabricated from materials that have film softening temperature ranges, having upper-end temperatures that are greater than an upper-end melting temperature of the fuel core melting temperature range such that the fuel core material becomes liquid substantially sooner than the film becomes non-self-supporting due to softening, so that when the candle burns, a pool of fuel core fuel material forms on the top of the candle, around the candle flame, without immediately causing the film to become non-self-supporting, and a portion of the molten fuel core material is consumed, so that an upper surface of the pool is vertically spaced from a top edge of the film.
As the candle burns down, the top edge of the film is exposed to progressively higher temperature regions of the aura of the candle flame, and ultimately becomes non-self-supporting and recedes downward from the descending candle flame, while the pool of molten fuel core material is further consumed, so that a vertical spacing between the upper surface of the pool of molten fuel core material and the top edge of the film is maintained.
Each of the at least two layers of the film are not readily soluble in the fuel core material. Preferably, at least one layer of the film may be fabricated from a material selected from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes. At least one layer of the film may be fabricated from a material selected from the group consisting of: polypropylene. The film has one of the following characteristics: transparent, translucent, opaque.
The film preferably includes at least one active ingredient from the group consisting of: fragrance materials, air freshener materials, insect repellent materials, flame retardant materials, dyes, pigments, plasticizers.
The invention also is directed, in part, to a method for making a candle unit, comprising the steps of:
forming a supporting film for a candle, the supporting film being substantially self-supporting at ambient room temperature,
forming a fuel core and positioning a wick in the fuel core material,
substantially surrounding the fuel core with the supporting film;
the fuel core having a melting temperature range, the film being fabricated from at least one material, having a film softening temperature range, having an upper-end temperature that is greater than an upper-end temperature of the fuel core melting temperature range such that the fuel core material becomes liquid substantially sooner than the film becomes non-self-supporting due to softening, so that when the candle burns, a pool of molten fuel core fuel material forms on the top of the candle, around the candle flame, without immediately causing the film to become non-self-supporting, and a portion of the molten fuel core material is consumed, so that an upper surface of the pool is vertically spaced from a top edge of the film;
whereupon as the candle burns down, the top edge of the film is exposed to progressively higher temperature regions of the candle flame, and ultimately becomes non-self-supporting and recedes downward from the descending candle flame, while the pool of molten fuel core material is further consumed, so that a vertical spacing between the upper surface of the pool of molten fuel core material and the top edge of the film is maintained.
The supporting film is further fabricated from at least one material that is not readily soluble in molten fuel core material.
The step of forming a supporting film further comprises the step of fabricating the supporting film from a material from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes. The supporting film may have a single layer. Alternatively, the supporting film may have at least two layers. The at least two layers may be fabricated from different materials. Preferably, each of the at least two layers of the supporting film are not readily soluble in the fuel core material.
Preferably, at least one layer of the supporting film is fabricated from a material selected from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxances. At least one layer of the supporting film may be fabricated from a material selected from the group consisting of: polypropylene.
The film has one of the following characteristics: transparent, translucent, opaque. The supporting film may include at least one active ingredient from the group consisting of: fragrance materials, air freshener materials, insect repellent materials, flame retardant materials, dyes, pigments, plasticizers.
The steps of
forming a supporting film for a candle,
forming a fuel core and positioning a wick in the fuel core material, and
substantially surrounding the fuel core with the supporting film, further comprise the steps of:
forming the supporting film into a container shape,
pouring fuel core material into the container shape and positioning the wick in the fuel core material; and
permitting the fuel core material to solidify, at least partially.
The invention is also directed to a method for making a candle unit, comprising the steps of:
forming a supporting film for a candle, the supporting film being substantially self-supporting and formed from at least two layers, fabricated from different materials;
forming a fuel core and positioning a wick in the fuel core material,
substantially surrounding the fuel core with the supporting film;
the at least two layers being fabricated from materials that have film softening temperature ranges, having upper-end temperatures that are greater than an upper-end melting temperature of the fuel core melting temperature range such that the fuel core material becomes liquid substantially sooner than the film becomes non-self-supporting due to softening, so that when the candle burns, a pool of fuel core fuel material forms on the top of the candle, around the candle flame, without immediately causing the film to become non-self-supporting, and a portion of the molten fuel core material is consumed, so that an upper surface of the pool is vertically spaced from a top edge of the film;
whereupon as the candle burns down, the top edge of the film is exposed to progressively higher temperature regions of the candle flame, and ultimately becomes non-self-supporting and recedes downward from the descending candle flame, while the pool of molten fuel core material is further consumed, so that a vertical spacing between the upper surface of the pool of molten fuel core material and the top edge of the film is maintained.
Preferably, each of the at least two layers of the supporting film are not readily soluble in molten fuel core material. The step of forming a supporting film preferably further comprises the step of forming the supporting film from a material from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes. Preferably, at least one layer of the film is fabricated from a material selected from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes. Preferably, at least one layer of the film is fabricated from a material selected from the group consisting of: polypropylene. Preferably, the film has one of the following characteristics: transparent, translucent, opaque.
The film may include at least one active ingredient from the group consisting of: fragrance materials, air freshener materials, insect repellent materials, flame retardant materials, dyes, pigments, plasticizers.
The steps of
forming a supporting film for a candle, the supporting film being substantially self-supporting,
forming a fuel core and positioning a wick in the fuel core material, and
substantially surrounding the fuel core material with the supporting film, further comprise the steps of:
forming the supporting film into a container shape,
pouring fuel core material into the container shape and positioning the wick in the fuel core material; and
permitting the fuel core material to solidify, at least partially.
The invention is also directed to a method for forming a cased article, comprising the steps of:
forming a casing from a self-supporting film unit;
pouring a liquid gel material into the casing; wherein the self-supporting film structure is fabricated from one or more materials, each of which is insoluble in the liquid gel material.
The self-supporting film structure may be fabricated from at least two layers. At least one of the at least two layers may be a material from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes; and another of the at least two layers is fabricated from the group consisting of polypropylene.
The invention is also directed to a method for forming a cased article, comprising the steps of:
forming a casing from a self-supporting film structure; and
pouring a liquid gel material into the casing; wherein the self-supporting film structure is fabricated from one or more materials, wherein the self-supporting film structure is fabricated from at least two layers.
At least one of the at least two layers may be a material from the group consisting of: cyclic olefin copolymers (etc.); and another of the at least two layers is fabricated from the group consisting of polypropylene.
The self-supporting film structure may be fabricated from one or more materials, each of which is not readily soluble in the liquid gel material.
The invention is also directed to a method for forming a cased article, comprising the steps of:
forming a gel structure having an exterior surface; and
forming a substantially self-supporting film in one or more sheet portions;
wrapping one or more sheet portions of the substantially self-supporting film around at least portions of the gel structure;
joining adjoining edges of the one or more sheet portions, to form a casing surrounding at least a portion of the gel structure.
The self-supporting film structure may be fabricated from at least two layers. At least one of the at least two layers is a material from the group consisting of: cyclic olefin copolymers, polyhedral oligomeric silsesquioxanes; and another of the at least two layers is fabricated from the group consisting of polypropylene.
The self-supporting film structure may be fabricated from one or more materials, each of which is substantially insoluble in the liquid gel material.
In an embodiment of the invention, each of the film and the fuel core has one of the following characteristics: transparent, translucent. In an embodiment of the invention, the film has a surface that has been contoured to form a Fresnel lens.
The present invention is also directed to a candle unit, comprising a fuel core, fabricated from a flammable fuel material, the fuel material having one of the following characteristics: clear, translucent, transparent; and having a first index of refraction. A wick is embedded in the fuel core, for drawing up molten fuel material, for supporting a candle flame. A film surrounds at least a portion of the fuel core, the film having one of the following characteristics: clear, translucent, transparent; and having at least a second index of refraction. The fuel core and the film together forming a candle body. The indicies of refraction of the fuel core and the film are operably configured so that upon lighting of the candle, at least a portion of the light radiated from the flame enters the fuel core and is reflected and/or refracted within the fuel core, prior to emanation as light emanating from the candle body.